That's a problem with cell-phone providers who overcharge for SMS. An SMS is almost free nowadays, in some cases it actually is free since it goes over channels that would otherwise go unused. SMS seems like a good, cheap, ubiquitous solution for most of the developed world.
From horrible providers, yes. The big three legacy operators in Canada charge 15 or 20 cents per unless you're specifically on a plan that includes a larger allowance.
It's easy to negotiate to get them for free when you have any amount of leverage on the provider, but out of the box you pay.
It depends on your contract. In general, by default, you pay a bit for every text (10 cents maybe?). But you have the option of paying a flat rate for unlimited texting, which is generally something like $10/month. Most people I know choose that option.
Let me ask again the parents question for clarification. Do people really pay for the received sms-es? It sounds like total bullshit, because you don't have an option not to receive sms from a person, like you have with calls.
Absolutely (in the US here). Some carriers will allow you to block all text messages, which can get rid of the annoying ones you wouldn't want to accept, but also forces legitimate ones to get eaten - causing some people to think you're ignoring them when you actually had no idea they even tried texting you in the first place.
Being forced to pay a small fee (by your phone-service provider) to log in isn't much better, I think.